Correlates and effect of suboptimal radiotherapy in women with ductal carcinoma in situ or early invasive breast cancer.
BACKGROUND
The study aimed to identify factors associated with less-than-optimal radiotherapy (RT) and its impact on disease-free survival in women aged 66+ years diagnosed with stage I breast cancer or ductal carcinoma in situ (DCIS).


METHODS
The subjects were women diagnosed from 1991 to 1999 in the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database who underwent breast-conserving surgery and RT within 12 months postdiagnosis. The authors conducted descriptive and multivariate survival analyses, and considered age, race, poverty, marital status, comorbidity indices, rural/urban, radiation oncologist density, comedo necrosis histology (DCIS only), chemotherapy receipt (stage I only), and RT completion (3+ weeks of treatment) and delay (8+ weeks postsurgery without chemotherapy; 4+ weeks postchemotherapy).


RESULTS
Of 7791 subjects, 16% experienced RT delay, and 3% had incomplete RT. Subjects with stage I disease who were more likely to delay RT were of black race (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.17-2.08), whereas women in areas of high radiation oncologist density were less likely to delay (OR, 0.73; 95% CI, 0.66-0.81). Those living in high poverty areas were less likely to complete RT (P < .03), as were those undergoing chemotherapy (OR, 1.82; 95% CI, 1.15-2.88). Stage I breast cancer patients with delayed RT were more likely to experience a subsequent breast event (OR, 1.14; 95% CI, 1.00-1.30), and those with incomplete RT had a higher rate of overall mortality (OR, 1.32; 95% CI, 1.06-1.63). Factors associated with lower subsequent breast events included older age, lower poverty, and being married. RT delays of 12+ weeks (or 8+ weeks postchemotherapy) had a strongly negative impact on subsequent events (OR, 3.94; 95% CI, 2.51-6.17 for DCIS; OR, 2.77; 95% CI, 1.84-2.59 for stage I).


CONCLUSIONS
RT should be facilitated to ensure completion and timeliness, especially for early invasive breast cancer patients.
Gold
Heather Taffet
HT
Weill Cornell Medical College, New York, New York 10021, USA. heg2001@med.cornell.edu
Do
Huong T
HT
Dick
Andrew W
AW
D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery; D002278:Carcinoma in Situ / Q000532:radiotherapy; D018270:Carcinoma, Ductal, Breast / Q000401:mortality / Q000532:radiotherapy / Q000601:surgery; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015999:Multivariate Analysis; D011878:Radiotherapy / Q000379:methods*; D011879:Radiotherapy Dosage; D018426:SEER Program; D013997:Time Factors